Help me get my brain around this cooling issue.

[teamgs]

Greets,
Over the past few days, when I arrive at my destination and shut off the car, the coolant violently boils over into the overflow tank. While driving, the temp gauge reads pretty much as it always does. While idling, I don't see any boiling over, only once I shut off the engine. The top radiator hose from the radiator to the engine blows up like a balloon.

I thought it might be a weak radiator cap, so I replaced it with a new 16lb unit this morning, and low and behold, no boilover when I arrived at work after 50 miles of driving. However, this evening, after I arrived home, it started again after I shut off the motor. I restarted the car, and let it idle, and the spitting out of the coolant subsided, only to continue when I shut off the car again.

Any ideas? I assumed that if it was a head gasket leak, that it would cause issues while running as well, correct? I have a pretty new 180 deg thermo, and removed and inspected it the other day.

Regards,

Gary

 

[94TURBO5 O]

You need to try and fill it all the way up and squeeze the hoses to get the air out. Called basically burping the system.

 

[bjl95mustang]

You can also jack up the fron of the car and run it with out the rad cap on. Let it get warm and get hot so the t-stat will open. some of the coolant will come out of the rad neck but just add coolant ass needed. This will also help you bleed air out.

After you do this look at the over flow bottle with the cap on and see if you can see bubbles in there.

 

[teamgs]

Thanks guys,
It didn't boil over this morning either. I know it's about 15 degrees cooler in the morning than the evening, but I am not sure this would be a major issue, as it is still in the mid 70's - 80's tops.

Question regarding the burping: The presence of air bubbles could cause this issue how? Is the air pocket blocking the flow of coolant, and thus preventing the guage from reading correctly?

Regards,

Gary

 

[94-302-vert]

There is a good chance that the air si the system is allowing the coolant to basically overheat locally. Try to burp the system as best you can and see if that helps.

When/how did this start?

 

[teamgs]

Hey Chris,
Started a week or so ago. Nothing was done to the car. BTW, It hasn't boiled over since I posted this question. Possibly, if it was indeed an air pocket, that it passed. Very odd...

Thanks ,

Gary